In today's airport environment, safely and efficiently navigating aircraft from the time an aircraft has entered controlled airspace and while the aircraft is maneuvered during ground travel after landing and then to a runway prior to takeoff presents challenges for all concerned with this process. Increased numbers of flights and larger aircraft that must use airport facilities not designed to handle them has contributed to these challenges. Airline regulatory agencies, aircraft manufacturers and airlines have worked to achieve a high level of flight safety by investing in overlapping safety systems that prevent errors which have effectively improved the safety of aircraft in flight. Airport ground operations, however, have not yet achieved a comparable level of safety. A recent estimate indicated that the aircraft industry losses for physical damage resulting from accidents and incidents on the ground can approach US$11 billion annually. The systems employed to produce the aforementioned high levels of flight safety, unfortunately, are not transferrable to ground operations. The congested nature of airport ramp areas and taxiways coupled with time pressures to move aircraft as quickly as possible between arrival and departure produces situations in which ground incidents, including collisions between aircraft, ground service vehicles, and other objects and obstacles, leading to injuries are not only possible, but very likely.
Increasing the safety of aircraft ground movement between landing and takeoff and minimizing the likelihood of ground incidents are being addressed, and aircraft systems that can improve aircraft ground safety have been proposed. In U.S. Pat. No. 7,113,202 and related U.S. Patent Application Publication No. U.S.2010/0241291 to Konya, for example, an automatic taxi control system that controls the direction of aircraft ground travel is described. An “autotiller” concept is used to automatically and precisely control aircraft nose wheel steering to maintain aircraft travel along a desired nose wheel taxiline as the aircraft maneuvers through limited taxi and parking space by precisely sensing and computing and correcting for nose wheel deviation from the taxiline. The path of aircraft travel may be sensed by a video tracking system that uses the aircraft's onboard taxi camera system with appropriate sensors that may be on the aircraft or on the ground, a tracking control system, and the nose gear steering system. The provision of emergency automatic collision avoidance steering/braking means is also suggested. This system is tied specifically to the aircraft steering system to provide automatic taxiing capability, including the turning choice decision at taxiway intersections based on a digital airport map and GPS-guided locator, with little or no pilot input.
The WingWatch aircraft ground collision avoidance system described at www.scss.tcd.ie/Gerard.Lacey describes an obstacle detection system using different types of sensors that can be mounted on aircraft or ground service vehicles to detect the presence of objects, including aircraft, other vehicles, persons, and the like, within an area around an aircraft that are potential collision threats. Sensors preferred for this purpose are cameras mounted at specific positions on the aircraft used in combination with computer vision techniques and software in communication with a pilot warning interface.
U.S. Pat. No. 7,379,014 to Woodell et al describes a radar system to be used during aircraft taxi to detect obstacles. This system is stated to be more reliable than cameras, which are asserted to fail under some precipitation situations in which the disclosed radar system effectively detects obstacles that could pose collision hazards. In U.S. Pat. No. 6,118,401, Tognazzi discloses an aircraft ground collision system and method that can be used during taxi or towing. This system includes both a video and a radar unit mounted in an aircraft wing tip to detect proximity of an object coupled with an audio or visual warning indicator that a collision is imminent. The aircraft ground collision avoidance system described by Stone et al in U.S. Patent Application Publication No. U.S.2007/0080848 uses a processor, transceiver, and memory to process, communicate, and store information relating to two aircraft that will enhance situational awareness and prevent collisions.
While the foregoing patents and publications may describe systems and devices that can improve aircraft ground travel efficiency and safety, they do not suggested that these system or devices could be adapted for use in monitoring or controlling the ground movement of aircraft that are autonomously and independently driven on the ground by non-engine drive means. In U.S. Patent Application Publication No. U.S.2011/0259995, Frings et al describes a method for moving an aircraft along the ground using at least two separate appliances, described as tractors, which are attached to and detached from the aircraft main landing gear to move the aircraft on the ground without the aircraft engines. Cameras on the appliances are provided to ensure that the appliances are properly approaching the aircraft landing gear and that the landing gear has not been damaged when the appliances are detached. While the system described by Frings et al may provide a way to move an aircraft without using the aircraft's main engines, it does not monitor or control aircraft ground movement in response to monitoring. Moreover, the appliances used to move the aircraft are separate structures that must be returned to a ramp or gate area for reuse and, therefore, could increase congestion in an area already crowded with aircraft and accessory ground vehicles. In U.S. Pat. No. 7,445,178, McCoskey et al describes a precision guidance system requiring ground elements that interact with aircraft elements to control the direction of movement of an aircraft on the ground during taxi with a powered nose aircraft wheel system. It is not suggested that the guidance system of McCoskey et al, which is specifically directed to aircraft ground travel route control, could function without the tarmac guidance elements. McCoskey et al, moreover, is otherwise silent with respect to a system for monitoring and controlling aircraft ground movement that controls operation of a non-engine drive means to move an aircraft as required to avoid collision and enhance the safety or efficiency of airport ground operations without the use of ground-based or like structures in the airport environment.
Commonly owned U.S. Pat. No. 7,983,804 to Cox et al describes a system for minimizing aircraft damage on collision in a vehicle, including an aircraft, with at least one self-propelled nose wheel. This system, which has a motor in the self-propelled wheel, includes means for measuring the speed of travel and torque of the wheel and monitoring the torque or the torque:speed ratio and signaling the motor to stop when the torque or the torque:speed ratio exceeds a given value that may be indicative of resistance caused by a colliding obstacle, including a rut in the ground surface. Substantially constant monitoring of speed and torque allows the motor to be stopped automatically or manually when a warning is communicated to the pilot before damage is caused by the collision. It is not suggested either that ground travel variables other than speed and torque could be monitored or that the aircraft could be monitored to provide automatic control of movement during independent ground travel to enhance the safety and efficiency of airport ground operations.
A need exists, therefore, for an improved monitoring and control system capable of providing automatic control of ground movement in one or more aircraft equipped with non-engine drive means to increase airport ground safety and the safety and efficiency of aircraft ground travel, thereby improving the efficiency of airport ground operations and enhancing the efficient utilization of airport facilities.